This invention relates to a method and apparatus for controlling the operation of Homogeneous Charge Compression Ignition (HCCI) engines over a wide range of speeds and loads. HCCI is a type of combustion in which a premixed fuel air mixture is brought to auto-ignition near the end of the compression stroke. Engines using HCCI combustion have the potential to meet future stringent emission standards with increased fuel efficiency and without penalty in production cost. Engines operating with HCCI combustion can be used for passenger cars, buses, trucks as well as non-road and off-road applications.